Search

Overall improvement in the interpretation of images obtained in the emergency department and involvement in decision making will reinforce the participation of radiology in the local stroke team and will increase the added value of radiology to stroke care.

To retrospectively determine the sensitivity and specificity of cerebral angiography for the diagnosis of primary angiitis of the central nervous system (CNS).Institutional review board approval was obtained, and informed consent was not required. Thirty-eight patients (13 men, 25 women; mean age, 55 years) had undergone cerebral angiography followed by cortical and leptomeningeal biopsy for possible primary angiitis of the CNS during an 8-year period. Angiography reports were reviewed by investigators blinded to the results of biopsy. Angiographic findings were categorized as typical for vasculitis, normal, or other. Sensitivity and specificity of cerebral angiography for the diagnosis of primary angiitis of the CNS were calculated.Fourteen patients had typical angiographic findings of vasculitis. None had primary angiitis of the CNS at brain biopsy (60% specificity). Specific pathologic diagnoses other than primary angiitis of the CNS were made in six patients. Findings of brain biopsy in the remaining eight patients were nondiagnostic. Repeat angiograms were obtained in three of the eight patients. One patient demonstrated interval improvement in multiple focal intracranial arterial stenoses and two demonstrated worsening. Primary angiitis of the CNS was found at biopsy in two of the remaining 24 patients (0% sensitivity). One of the two patients had slow filling of a single distal cortical artery, and the other patient had multiple regions of abnormally prolonged capillary blush.In this series, patients suspected of having primary angiitis of the CNS on the basis of clinical and angiographic findings did not have primary angiitis of the CNS at biopsy. Typical angiographic findings of primary angiitis of the CNS are often associated with other specific pathologic diagnoses, which emphasizes the importance of brain biopsy.

To evaluate safety-related issues and imaging artifacts of Guglielmi detachable coils in vitro with 3-T magnetic resonance (MR) imaging.Two aneurysm models were constructed: one from porcine carotid artery and the other from a pharmaceutical capsule. Both were filled with Guglielmi detachable coils. The models were tested with a 3-T MR imager for heating, deflection, and imaging artifact. Testing for heating and deflection was performed (a) at static points both inside and outside the bore, (b) during movement into the imager, and (c) during clinical imaging sequences.No change in temperature was measured during movement into the imager bore or at different points within the bore. No differences in heating from radio-frequency energy were found between aneurysm models and controls. Similarly, no evidence of deflection of the coil mass (capsule model) was found. Minor susceptibility artifacts were found in the readout direction during gradient-echo sequences. Magnetic field mapping showed no induced field inhomogeneity.MR imaging at field strengths of 3 T in patients with aneurysms treated with Guglielmi detachable coils is safe. Imaging artifacts are likely to be minimal.

To test the ability of a count-based positron emission tomographic (PET) method, without arterial sampling, for the measurement of regional cerebral oxygen extraction fraction (OEF) to predict ischemic stroke in patients with symptomatic carotid arterial occlusion.The outcome analysis of a blinded prospective study designed to determine if increased OEF was an independent predictor of stroke in patients with symptoms and with carotid occlusion was repeated by substituting a count-based method of OEF measurement for the original quantitative technique. The performance of the quantitative and count-based methods was assessed by using Kaplan-Meier cumulative survival functions (log-rank, [p.05]). Receiver operating characteristic (ROC) curves for both methods were generated.Thirteen ipsilateral strokes occurred during a mean follow-up of 3.1 years for 81 patients. All ipsilateral strokes occurred in 50 patients with increased count-based OEF (P = .002, sensitivity 100%, specificity 46%). Sixty-eight patients underwent complete quantitative studies, which allowed comparison of OEF methods. Both the count-based and the quantitative methods were predictive of stroke in this subgroup (P = .005 and .025, respectively). ROC analysis demonstrated a greater area under the curve for the count-based OEF method.Count-based PET measurement of OEF without arterial sampling accurately predicts stroke in patients with carotid occlusion.

To compare quantitative values of cerebral blood flow (CBF) derived from dynamic susceptibility contrast (DSC) magnetic resonance (MR) imaging with reference standard positron emission tomography (PET) in patients with confirmed cerebrovascular occlusive disease.Local institutional review board approval and informed consent were obtained for a prospective study of 18 patients (six men, 12 women; age range, 28-71 years; mean age, 45 years ± 10.4 [standard deviation]) with angiographically confirmed Moyamoya (n = 8) or internal carotid artery occlusions (n = 10). DSC MR images and oxygen 15-labeled water (H(2)[(15)O]) PET images were acquired on the same day. DSC images were postprocessed to yield parametric images of CBF (in mL/100 g/min), coregistered, and analyzed using grid-based regions of interest. Mean values of CBF in each region of interest from MR imaging and PET data sets were compared. Correlations for each patient were determined and overall agreement between pooled MR imaging and PET CBF was reported using linear regression analysis and Bland-Altman plots.Strong correlations (r(2) ≥ 0.55) were found between MR imaging and PET CBF values in all patients. Use of the bookend approach was found to underestimate CBF predictably across the patient cohort (mean slope, 0.82; standard deviation, 0.18; slope of aggregated data, 0.75). This allowed for a simple rescaling of MR imaging values producing strong agreement with PET values in the aggregated data (r(2) = 0.66; slope = 1.00; intercept = 0.00).The data show that the bookend MR imaging technique produces similar results for quantitative CBF between DSC MR imaging and H(2)[(15)O] PET. Although MR-derived CBF underestimated PET-derived CBF, the patient-to-patient variability in the slopes of the linear MR and PET relationships was significantly smaller than a competing quantitation technique. As a result, the bookend technique appears to more predictably measure quantitative CBF in a clinical setting.

Perfusion imaging in acute ischemic stroke is a promising technique; we have a responsibility to design research studies that increase the understanding of the role of this tool in acute ischemic stroke treatment by enrolling more patients in research studies rather than jumping the gun and using the tool as a clinical aid.

To determine the value of arterial sheaths in diagnostic neuroangiography in a randomized controlled trial.A total of 842 patients (411 men, 431 women; mean age, 59.4 years; age range, 29.5-94.3 years) undergoing diagnostic neuroangiography were randomly assigned to groups in which a sheath was introduced immediately after puncture of the femoral artery (sheath group) or in which a diagnostic catheter was introduced without a sheath (control group). Two hundred twenty-four (26.7%) of 839 patients were receiving anticoagulants immediately prior to the procedure.Complications (mostly small hematomas of the groin) occurred in 106 (12.6%) of 842 patients, with no difference between groups (53 [12.6%] of 421 patients in both; P.99). Ease of catheter manipulation was greater in the sheath group than in the control group. Incidence of bleeding at the femoral puncture site during the procedure was less in the sheath group (seven [1.7%] of 421 patients) versus the control group (150 [35.6%] of 421 patients), with a P value less than.001. Because of bleeding, sheath insertion was necessary in 165 (39.2%) of 421 patients in the control group. This crossover group also had a higher rate of local complications (28 [17.0%] of 165 patients) than the sheath and control groups. Serious complications, such as stroke (one [0.12%] of 842 patients) and transient ischemic attacks (five [0.60%] of 842 patients), occurred with equal frequency in both the sheath and control groups.Use of arterial sheaths lessens the incidence of intraprocedural bleeding at the femoral puncture site and increases ease of catheter manipulation without increasing the number of groin complications.

To correlate the size and location of intracranial aneurysm with the need to reposition the aneurysm clip after intraoperative angiography.In 199 consecutive patients with 234 clipped intracranial aneurysms, 273 intraoperative angiographic studies were retrospectively reviewed. Aneurysm size and location, determined with preoperative angiographic and surgical reports, were correlated with the frequency of clip repositioning because of parent- or branch-vessel compromise or unexpected residual aneurysm.Findings from intraoperative angiograms resulted in clip repositioning in 46 of 273 (16.8%) studies. Clip repositioning was statistically significantly less frequent with aneurysms of the posterior communicating (three of 52 [5.7%] studies) and anterior choroidal (none of 12 studies) arteries. High rates of clip repositioning were found in aneurysms of the superior hypophyseal artery (seven of 18 [38.9%] studies), superior cerebellar artery (three of five [60.0%] studies), and bifurcation of the internal carotid artery (three of nine [33.3%] aneurysms). In 98 conventional follow-up angiographic studies, seven (7%) false-negative cases with unsuspected aneurysm neck remnant were found.The rate of clip repositioning in aneurysms of the posterior communicating or anterior choroidal arteries was less than that at other locations (P.05). Intraoperative angiography may not be necessary when aneurysms are at these two locations.